Lukas Podolski is poised to join Arsenal from Köln at the end of the season after the clubs reached an agreement in principle on a £10.9m transfer. The Germany striker is expected to sign a four-year contract worth £100,000 a week, according to sources in Germany.

Arsène Wenger has been under pressure to bolster his attacking options because the cover behind Robin van Persie, the captain, has looked thin, with neither Marouane Chamakh or Park Ju-young having convinced.

Van Persie, who is close to the final 12 months of his Arsenal deal and has placed new contract talks on hold until the summer, must also be persuaded about the club's ambition.

Podolski's arrival would represent a coup and it reinforces Wenger's shift in transfer policy towards more established players. Still only 26, the Poland-born forward has played at the highest level since his late teens, when he broke into the Germany squad. He has enjoyed a positive season, with 16 Bundesliga goals so far, but he has grown disillusioned at Köln's direction. They languish just above the relegation places, with 25 points from 24 games.

Podolski, who was at Bayern Munich from 2006 to 2009 before rejoining his former club, has been quiet about his possible move to Arsenal but the Köln manager, Stale Solbakken, admitted last month that he feared he was set to lose the forward to the London club.

Lokomotiv Moscow and Anzhi Makhachkala were also understood to have been chasing Podolski, and could have offered bigger money, but he said recently his move would not be determined by the highest bidder. "Money is not the most important thing for me," he told Sport-Bild. "What is crucial is the development of my game."

Per Mertesacker, a Germany team-mate who moved from Werder Bremen to Arsenal last summer, told German television on Wednesday that Podolski had been asking him about life at the Emirates. "He has been very interested for the past few weeks," Mertesacker said. "He has sent me a number of text messages, and I have told him this is a great place to work and Arsenal are an amazing club."